1. Field of the Invention:
The present invention relates to a heat pump refrigeration system employing a hermetic motor compressor wherein compressed refrigerant passes over the motor prior to being discharged into the system, and more particularly, to an automatic valved system for providing cooling of the refrigerant discharged from the compressor prior to its passage over the motor when the system is operating in the cooling cycle. The valved system further provides for the storage of excess refrigerant when the refrigeration system is operating in the heating cycle.
2. Description of the Prior Art:
The present invention is employed in conjunction with a hermetic motor compressor of the type disclosed in U.S. Pat. Nos. 3,105,633-Dellario and 3,109,297-Rinehart, both being assigned to the General Electric Company, assignee of the present invention. Both of the above patents disclose means for cooling the motor to maintain its temperature within safe operating limits. The method of motor cooling employed by the above patents is to pass the high pressure discharge gas from the compressor unit over the motor after this high pressure gas has been cooled to a low enough temperature to remove heat from the motor. More particularly, liquid refrigerant is injected into the semi-compressed gas in the compression chamber so that temperature of the discharge gas is lowered prior to its passage into the casing and over the motor.
It has been recognized in the art that optimum operation of heat pumps on the cooling cycle, i.e., when the indoor heat exchanger is being used as an evaporator, requires a greater effective charge of refrigerant than that required for operation on the heating cycle, when the indoor coil is functioning as the condenser. Accordingly, many attempts have been made to solve this problem. U.S. Pat. No. 3,110,164-Smith discloses one of the prior art systems employed for accumulating a portion of the refrigerant charge during the heating cycle and for restoring the accumulated portion of the charge to the system during the cooling cycle.